This invention relates to telescoping seating systems. More particularly, the invention relates to tier catches for releasably locking telescopic seating platform sections.
Conventional telescopic seating systems are compilations of individual repeatable segments known as platforms or decks. A single platform is comprised of the following components. A rear riser beam that runs transversely along the length of the deck forms the main carrying support for the platform and is situated at the back of the platform. The rear riser beam is typically a continuous rectangular piece of steel with the width of the riser having a vertical orientation relative to a substrate such as a floor on which the seating system is placed. The riser is fabricated with a rear flange that extends from a bottom end of the riser toward the front of the platform. The flange provides a surface for mounting other components of the platform.
Situated at the front of the platform is a nose beam that defines the front edge of the platform. The nose beam is typically fabricated from extruded aluminum, tube steel or shaped into a partial tube from sheet steel. The top front edge of the nose beam is radiused to provide comfortable seating conditions if no further seating components are added to the platform. Nose beams constructed from extruded aluminum or sheet steel formed into a partial tube lacks the strength of a tube steel design but is far less expensive to manufacture. There is thus a need for a nose beam that has the strength of a tube steel design but which is cost efficient relative to the sheet steel open design.
Extending toward the back of the platform from the nose beam is a front flange that provides a mounting surface for further components of the platform. The front flange can be either a separate bar of steel welded onto the nose beam or a continuation of the sheet steel that forms the main body of the nose beam. Structural steel is the material of choice for the rear riser beam and the nose beam since these components are required to withstand the application of significant loads along their lengths. Of course, any durable material that is capable of withstanding the compression and tension forces imparted onto the beams can be utilized for these components.
The rear riser beam and nose beam are connected at their ends by a pair of lateral deck supports. The deck supports can be either bolted to or welded onto the transverse riser and nose beams. The rear riser beam and nose beam are also connected by deck supports situated between the lateral deck supports that are used to provide additional support for the decking material. The length of the particular deck determines the number of deck supports needed. Additional connections between the riser and nose beams are provided by cantilever sections of columns as described below. Both deck supports and cantilevers are made from formed steel.
The combination of the deck supports, the rear flange and the front flange provide a mounting surface for decking material which forms the surface to which further seating components are attached or upon which individuals sit. Almost invariably, plywood-based materials are used for the decking. In fact, the industry-standard 4xc3x978 feet sheet plywood is used which in turn, sets the standard for platform depths. In the conventional application, 4xc3x978 sheets of a multi-ply plywood product are ripped along its length to produce two 2xc3x978 feet sections. The platform frames to which the plywood sections are attached are sized to accommodate the 2xc3x978 sheets. Platforms are typically 26 inches deep.
To establish the height of a platform to a selected height, columns are provided, typically in pairs, which attach to the rear riser. Conventional columns for telescopic seating systems are constructed from tube steel because of the tube steel""s ability to withstand the multitude of forces applied to the platform when a load is applied.
Situated at or near the top ends of the columns are cantilevers, which extend toward the front of the platform. As stated, the cantilevers provide additional connections between the riser and nose beams. Formed within the cantilevers are linear channels or races for receiving roller wheels, which are attached to the tops of the columns. The channels are adapted to receive the column wheels of a platform that is immediately below and forward of the platform of which the channel forms a part thereof. By design, the mated wheels and channels are slidingly engageable. The wheels/channel assemblies provide a means for sliding adjacent platforms into either retracted/nested states or extended/used states. The cantilevers fully support the platforms in the retracted position.
The bottom ends of the columns are attached to castor horns. The castor horns provide a mounting base for wheels, which allow for the transitional movement of a platform from a retracted position to an extended position and vice versa. The castor horns are also typically made of steel and have features, which allow for the connection of adjacent castor horns that are part of adjoining platforms such as hooks that are adapted to be received in channels. Adjacent castor horns are adapted to be capable of sliding engagement with one another and are further capable of being releasably locked together when adjacent platforms are in an extended orientation. Castor horn engagement is provided by mating surfaces that do not extend the length of the castor horns.
To counter the various compression, tension and torque forces exerted on platform segments when placed under load, cross bracing is used. The braces are configured to attach a top end of a first column at a first end of a platform to the bottom end of a second column at a second end of the platform. Multiple cross bracing members can be used depending on the specific size and set up of a series of platforms which are joined to form telescopic seating systems.
A problem encountered with conventional telescopic seating systems is the means used to lock adjacent sections together when the telescopic seating system is partially or fully extended. Prior systems incorporate a lever lock that projects above the caster horn in conjunction with a trip bar typically located on the first row. An external handle or other device has to be used to activate the trip bar. As is well known in the art, individuals that use telescopic seating systems occasionally attempt to walk under the extended platforms to facilitate ingress or egress from the particular location. When negotiating through the maze of columns and caster horns, individuals often step on the caster horn lock mechanisms, especially the long lever arms protruding vertically. Due to the fragile design of the locks, damage and lock malfunction often result. Trip bar angles, which have to be precisely set often, have to be adjusted due to abuse. There is thus, a need for a lock system that is capable of withstanding physical abuse and maintaining full operational capability. In addition, there is desire to eliminate the trip bar which has to be precisely set to trip each lever lock at the correct time.
It is thus an object of the invention to provide a caster horn locking mechanism that eliminates the need for a trip bar and that withstands the abuse of individuals walking onto the locks without compromising the integrity or function of the lock. These and other objects and features of the invention will be understood from a review of the following description and drawings.
The invention described herein is a locking mechanism used to releasably lock adjacent platform sections together when in an extended orientation. The locking mechanism is designed to be self-engaging in that the need for a trip bar to initial telescopic seating retraction is eliminated. The locking mechanism is comprised primarily of a tier catch mounted on the outer side of a castor horn. The tier catch has a series of flanged surfaces for engaging an end guide of an adjacent castor horn to lock the castor horn to the adjacent castor and for tripping other tier catches when moving toward a nested or retracted position.
A tier catch tab is provided to act as the tripping component to trip other tier catches. Rear flanges are provided on the tier catches to allow for adjacent tier catches to nest when in an unlocked retracted position.
To promote the stability of the tier catches in a vertical unlocked position, a tier catch ramp is affixed to a castor horn side opposite that to which the tier catch is attached. The catch ramp acts as a physical support for a vertical unlocked tier catch to ensure damage is not imparted to the tier catch if a focused load, e.g., a person""s foot, is placed on the tier catch in an unlocked position.
The tier catch has an additional flange on an uppermost edge that provides a means for facilitating tier catch rotation into a vertical position past adjacent cantilevered columns. These and other features of the tier catch castor horn locking system will become apparent from a reading of the following detailed description in view of the drawings appended hereto.